is a measure of the average internal kinetic energy while is a measure of total internal energy.

The first part of the statement refers to temperature, which is indeed a measure of the average internal kinetic energy of the particles in a substance. Temperature indicates how fast the particles are moving; higher temperatures correspond to higher average kinetic energy.

The second part of the statement refers to internal energy, which is the total energy contained within a system. This includes both the kinetic energy of the particles (due to their motion) and the potential energy (due to the interactions between the particles).

In summary, temperature measures the average energy due to motion of the particles, while total internal energy takes into account both the motion and the arrangement of the particles.

In thermodynamics, this distinction is crucial for understanding how energy is transferred within a system and how it relates to heat and work. Understanding these concepts is fundamental in fields such as physics, chemistry, and engineering.